This invention relates to a power supply arrangement for providing auxiliary power to the electrical system of a building, such as from a standby generator or the like.
Portable generators are used in certain situations to supply electrical power to residential and commercial load circuits during a utility power outage. A system for interconnecting the generator with the load center of a building typically includes a power inlet box having a receptacle for receiving a plug extending from the generator.
The power inlet box is typically mounted to the exterior of a building, and is adapted for connection to a transfer switching mechanism which establishes an electrical path between the generator and the load center. The transfer switching mechanism typically includes a series of switches and circuit breakers, which are operable to supply power to certain selected circuits of the load center. The circuits of the transfer switching mechanism are wired to selected circuits of the load center, through wiring housed within a conduit extending between the transfer switching mechanism and the load center.
A typical transfer switching mechanism includes a housing provided with a power input receptacle. The remote power inlet box is wired to a power cord connected to a junction box, and the power cord is engageable with the power input receptacle of the transfer switching mechanism so as to provide power to the transfer switching mechanism from the generator. An alternative arrangement is illustrated in Flegel U.S. Pat. No. 5,895,981 issued Apr. 20, 1999, the disclosure of which is hereby incorporated by reference. In the ""981 patent, the transfer switching mechanism includes a terminal compartment within which a set of terminals is located. The terminals are wired to the switches of the transfer switching mechanism. A set of power input wires extend from the power inlet box, and into the terminal compartment of the transfer switching mechanism. The ends of the power input wires are connected to the terminals, to establish a direct, non-plug type connection between the power inlet box and the transfer switching mechanism.
It is an object of the present invention to provide a simplified transfer switching mechanism which establishes a non-plug type connection with a power input adapted for interconnection with an auxiliary power source such as a generator. It is a further object of the invention to provide such a transfer switching mechanism which does not utilize a terminal arrangement for establishing the connection between the power inlet box and the transfer switching mechanism, to thereby eliminate the space and expense involved in a terminal-type connection arrangement. It is a further object of the invention to provide such a transfer switching mechanism which is relatively simple in its components and construction, to thereby reduce the cost of the components of the transfer switching mechanism and the labor involved in assembly of the transfer switching mechanism. A still further object of the invention is to provide such a transfer switching mechanism which provides a simple, convenient and reliable arrangement for interconnecting the transfer switching mechanism with a power input arrangement.
In accordance with the invention, a power transfer device includes a housing and a series of switches mounted to the housing and interconnected with the electrical system of a building. A cavity or compartment is formed within the housing, and is accessible through an access opening defined by the housing. A series of lead wires are interconnected with the switches. The lead wires define ends which extend into and are located within the compartment. The ends of the lead wires are adapted for engagement with a power input interconnected with the auxiliary power source, such that the lead wires establish an electrical path between the power input and the switches.
The power input may be in the form of a series of power input wires which extend from a remote power inlet box, which includes a power input receptacle for receiving a plug-type connector extending from the auxiliary power source, such as a portable generator. In this embodiment, the power input wires are connected to the ends of the lead wires, such as by twist-on connectors. Once the appropriate connections have been made, the wire ends and connectors are placed within the compartment of the power transfer device housing. A cover is mounted to the housing over the access opening, so as to enclose the compartment within which the wire ends and the connectors are located.
In another form, a power input receptacle is mounted to the cover, which is adapted to be positioned over the access opening defined by the housing so as to enclose the compartment. The power input receptacle includes engagement structure for receiving a plug-type connector interconnected with the auxiliary power source. In one version, the ends of the lead wires are connected directly to the power input receptacle, and the cover is engaged with the housing such that the power input receptacle extends into the compartment along with the lead wires. In another form, a set of power input wires may be secured to the power input receptacle and adapted for connection to the ends of the lead wires by appropriate connectors, such as twist-on connectors. The power input receptacle, the lead wires and the power input wires are then received within the compartment when the cover is mounted to the housing over the access opening.
A strain relief arrangement is preferably engaged with the wire leads between the switches and the compartment. The strain relief arrangement is in the form of one or more strain relief members with which the lead wires are engaged. The strain relief members may be mounted to a stationary member located adjacent the compartment. The stationary member may be in the form of a transverse wall defined by the housing adjacent the compartment, and the strain relief members may be secured to a mounting plate adapted for connection to the transverse wall. Alternatively, the strain relief members may be mounted to a bracket member separate from the housing and adapted for engagement with the housing.
The invention further contemplates a method of supplying power from an auxiliary power source to a power transfer device having a series of switches, substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.